https://esta.cbp.dhs.gov/esta/ . The questions they ask, and the info they require is the same as we used to enter on the old Visa Waiver Form. You will get a reply almost straight away, useful to have a printer on-line so you can print it out and take with you. It is valid for at least two years, next time you go and it's still valid you can amend the details with your new flight and hotel etc.
If you Google searching for ESTA info you will likely get a list of companies who will do it for you FOR A FEE. That only leaves you with the old Custom's form to fill in on the plane, which will be handed to you by the crew, i.e. are you taking a lot of money or fodd stuffs etc?Take a pen with you
Peter
